High-resilience elastomer composite structure and preparation method thereof
By stacking magnetoelastics and using magnetic field-induced foaming technology to form an anisotropic pore structure, the problem of reduced sensitivity in traditional magnetoelastics when improving repeatability and stability is solved. This results in a magnetoelastic with high recovery rate and low modulus, thus improving the measurement accuracy of elastic pressure sensors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-04-10
AI Technical Summary
Traditional magnetic elastomers suffer from reduced sensitivity when improving repeatability and stability, and current technologies struggle to balance high resilience and high sensitivity.
By stacking a first magnetoelastic body and a second magnetoelastic body, with the angle between their magnetization directions being less than 180°, and combining a mirror symmetry design, an anisotropic foam structure is formed using porous materials and magnetic field-induced foaming technology. Combined with magnetization, a like-pole repulsive magnetic circuit is formed, providing additional restoring force.
A magnetoelastic material with high recovery rate and low modulus was achieved, which reduced the recovery time of the elastic pressure sensor and improved the measurement accuracy and stability.
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Figure CN121821902A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of elastic medium layer preparation, and more specifically, to a highly resilient elastomer composite structure and its preparation method. Background Technology
[0002] Capacitive elastic pressure sensors possess significant application potential in fields such as smart healthcare monitoring and human-computer interaction due to their advantages including low detection limit, low power consumption, and good temperature stability. Magnetoelastics, as the core of capacitive pressure sensors, directly affect the accuracy and stability of the elastic pressure sensor due to their recovery performance. Traditional magnetoelastics often improve the sensitivity of pressure sensors through microstructure design, but this suffers from poor repeatability and stability. Current technologies improve repeatability and stability by increasing the modulus, but this leads to a decrease in sensitivity.
[0003] Therefore, there is an urgent need for a method to prepare highly resilient elastomer composite structures. Summary of the Invention
[0004] In view of the above problems, the purpose of this invention is to provide a highly resilient elastomer composite structure and its preparation method, so as to solve at least one problem existing in the prior art.
[0005] In a first aspect, the present invention provides a highly resilient elastomer composite structure, comprising a first magnetoelastic body and a second magnetoelastic body stacked together, wherein the first magnetoelastic body layer has a first magnetization direction; the second magnetoelastic body has a second magnetization direction; the angle between the first magnetization direction and the second magnetization direction is less than 180°; wherein the first magnetoelastic body and the second magnetoelastic body are porous materials with a pore density of 10-1. 3 - 10 8 cells / cm 3 .
[0006] Furthermore, a preferred technical solution is that the first magnetization direction and the second magnetization direction are mirror-symmetrical with respect to the bonding surface.
[0007] Furthermore, a preferred technical solution is that the raw materials of the magnetic elastomer include: modified magnetic particles, flexible polymer and curing agent, wherein, by mass, the ratio of magnetic particles to flexible polymer is 1%-80%; and the ratio of flexible polymer to curing agent is 1:1-50:1.
[0008] Further, a preferred technical solution is that the flexible polymer is one of a thermosetting resin, a photocurable resin, and a photothermal dual-curing resin; the thermosetting resin is one of PDMS, Ecoflex, or EPDM; the photocurable resin is Aiglus30 or F39-T acrylate resin; the photothermal dual-curing resin is a modified epoxidized polybutadiene resin; the magnetic particles are one of samarium iron nitrogen magnetic powder, neodymium iron nitrogen magnetic powder, or neodymium iron boron / samarium cobalt permanent magnet powder; and the particle size of the magnetic particles is 0.5 μm to 50 μm.
[0009] Secondly, the present invention provides a method for preparing a highly resilient elastomer composite structure. The method includes: surface modification treatment of magnetic particles; dispersing the modified magnetic particles in an organic solvent to obtain a magnetic particle dispersion; heating and stirring the magnetic particle dispersion with a preset flexible polymer solution, removing the organic solvent to obtain a magnetic particle flexible polymer mixture; performing cross-linking curing and foaming treatment on the magnetic particle flexible polymer mixture and a curing agent under magnetic field conditions to obtain a magnetoelastic; taking two magnetoelastics, magnetizing the first magnetoelastic to obtain a first magnetoelastic with a first magnetization direction; magnetizing the second magnetoelastic to obtain a second magnetoelastic with a second magnetization direction; and stacking the first and second magnetoelastics to obtain a highly resilient elastomer composite structure; wherein the magnetization intensity is 30 kOe - 60 kOe; and the angle between the first magnetization direction and the second magnetization direction is less than 180°. It should be noted that during the heating and mixing of the magnetic particle dispersion with the preset flexible polymer solution, the mixing is achieved by a magnetic stirring device at a temperature of 60-80℃ and a rotation speed of 800-1200 rpm.
[0010] Furthermore, a preferred technical solution is that the pore density of the magnetoelastic is 10. 3 -10 8 cells / cm 3 .
[0011] Further, a preferred technical solution is as follows: Under magnetic field conditions, a method for obtaining a magnetoelastic body based on the magnetic particle flexible polymer mixture and a curing agent through cross-linking curing and foaming treatment includes: adding a curing agent to the magnetic particle flexible polymer mixture, stirring until homogeneous, and performing vacuum degassing treatment; then, under magnetic field conditions, subjecting the magnetic particle flexible polymer mixture to a partial cross-linking curing reaction to obtain a magnetoelastic body precursor; and subjecting the magnetoelastic body precursor to supercritical fluid foaming to obtain the magnetoelastic body; wherein the pressure is 5-30 MPa, the saturation time is 10-120 min, the foaming temperature is 80-180℃, and the foaming time is 5-60 s; the magnetic field strength is 30-300 mT. It should be noted that during the supercritical fluid foaming process, the foaming agent is CO2 or N2.
[0012] Further, a preferred technical solution is that, under magnetic field conditions, a method for obtaining a magnetoelastic body by cross-linking, curing, and foaming treatment based on the magnetic particle flexible polymer mixture and the curing agent includes: adding a curing agent and a pore-forming agent to the magnetic particle flexible polymer mixture, stirring evenly, and then performing vacuum degassing treatment; under magnetic field conditions, causing the magnetic particle flexible polymer mixture to undergo a foaming reaction and a cross-linking curing reaction; and removing the pore-forming agent to obtain the magnetoelastic body; wherein the pore-forming agent has a particle size of 1-500 μm, a volume fraction of 1%-50%, a curing temperature of 60-150℃, and a magnetic field strength of 30-300 mT. It should be noted that, for photocuring, the reaction conditions for the partial cross-linking curing reaction are a strength of 30 mW / cm². 2 Irradiate with ultraviolet light for 1-30 seconds; for thermosetting, the conditions for partial cross-linking curing reaction are a temperature of 60-150℃ and 10-60 minutes.
[0013] Furthermore, a preferred technical solution is that the pore-forming agent is one or more of sodium chloride, ammonium bicarbonate, ammonium carbonate, polyethylene glycol, and polyethylene oxide. It should be noted that the pore-forming agent is removed by ultrasonic leaching or heating, at a temperature of room temperature to 100°C, an ultrasonic power of 50-150W, with water changed every 4-8 hours, and the ultrasonic leaching time being 1-24 hours.
[0014] Thirdly, the present invention provides an elastic pressure sensor, comprising using an elastomer composite structure as described above as an elastic medium layer.
[0015] This invention discloses a method for preparing a high-resilience elastomer composite structure. The invention effectively reduces the overall compressive modulus of the magnetoelastic by using foaming technology, avoiding the problem of excessively high modulus caused by simply adding solid fillers. Through magnetic field induction and the synergistic effect of the foaming process, a magnetoelastic with an anisotropic porous structure is obtained, and a unique internal like-pole repulsive magnetic circuit is formed by magnetization. Simultaneously, utilizing the like-pole repulsion effect formed after magnetization, additional restoring force is provided after the external force is removed, achieving a high recovery rate. Furthermore, by stacking two layers of porous magnetic elastomers with the same structure together, the recovery is aided by magnetic force, thereby further reducing the recovery time of the elastic pressure sensor and improving the recovery rate, successfully solving the industry problem of the incompatibility between low modulus and high recovery.
[0016] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description
[0017] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings: Figure 1 A schematic diagram of the structure of the magnetoelastic body before magnetization in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of the magnetoelastic body after magnetization according to an embodiment of the present invention; Figure 3 A schematic diagram of the highly resilient elastomer composite structure provided in this invention; Figure 4 A schematic diagram of the principle of the highly resilient elastomer composite structure under pressure provided by the present invention; In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation
[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.
[0019] It should be noted that the endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0020] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.
[0021] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.
[0022] For the high-resilience elastomer composite structure of the present invention, the magnetic particles that are mirror-symmetrical along the bonding surface have a reduced angle between their arrangement direction and the bonding surface during compression. The distance between magnetic particles in the same layer and between two layers is closer, and the interaction between like poles is enhanced. When the external pressure decreases or is removed, the magnetic force helps the medium layer recover, thereby reducing the recovery time of the elastic pressure sensor, improving the recovery rate, and thus improving the measurement accuracy of the elastic pressure sensor.
[0023] Example 1 Step 1: Preparation of surface-modified magnetic particles Take 50 g of samarium iron nitrogen magnetic powder with a particle size of 0.5 μm and place it in a 500 mL beaker. Add 200 mL of anhydrous ethanol, disperse by mechanical stirring, and then add 3 g of silane coupling agent KH550. Graft the magnetic particles by continuously stirring in a 60 °C water bath for 4 hours. After the reaction is complete, collect the modified magnetic powder by centrifugation at 8000 r / min, wash it three times with ethanol, and then dry it in a vacuum drying oven at 80 °C for later use.
[0024] Step 2: Preparation of a mixture of magnetic particles and flexible polymer. The surface-modified magnetic particles were mixed with 100 mL of n-hexane solvent and then subjected to ultrasonic treatment at 150 W for 30 minutes to form a uniform magnetic particle dispersion.
[0025] Take 100g of Sylgard 184 A PDMS prepolymer, mix it with the magnetic dispersion, place it in a 60℃ water bath, and magnetically stir at 1000 rpm for 120 minutes to make the particles uniformly dispersed and the n-hexane completely evaporated, thus obtaining a uniform magnetic particle flexible polymer mixture.
[0026] Step 3: Foaming and Cross-linking Curing 10 g of PDMS curing agent, Sylgard 184 B, was added to the obtained magnetic particle flexible polymer mixture, and the mixture was manually stirred for 5 minutes to achieve initial mixing. The mixture was then placed in a vacuum drying oven and degassed at -0.095 MPa for 15 minutes to remove air bubbles introduced by stirring. The curing agent is a compound capable of crosslinking with the hydroxyl groups in the flexible polymer.
[0027] The degassed mixture is placed into a custom mold, and a parallel magnetic field of 100 mT is applied while heating at 100°C for 30 minutes to allow partial cross-linking and curing, thus obtaining a magnetoelastic precursor. Using CO2 as a physical foaming agent, the magnetoelastic precursor was transferred to a high-pressure reactor for critical physical foaming. The saturation pressure was controlled at 20 MPa, the saturation time at 120 minutes, and the foaming temperature at 160℃. The pressure was rapidly released, and the foaming state was maintained for 20 seconds to allow the material to complete foaming and full cross-linking curing. The magnetic field was then removed, yielding a magnetoelastic with an anisotropic pore structure.
[0028] The obtained magnetoelastic body was observed to obtain, as shown in the figure. Figure 1 The magnetoelastic body shown has an internal porous structure and a distribution of magnetic particles.
[0029] Step 4: Magnetization Treatment The prepared magnetoelastic was magnetized in a uniform magnetic field of 45 kOe. This yielded the magnetoelastic of Example 1, which possesses a porous structure and magnetic particles.
[0030] The obtained magnetoelastic body was observed to obtain, as shown in the figure. Figure 2 As shown, the magnetoelastic body has an internal pore structure and a distribution of magnetic particles. After magnetization, the magnetic poles of the magnetic particles are aligned.
[0031] Step 5: Preparation of composite elastomer Two magnetoelastic bodies, a first magnetoelastic body and a second magnetoelastic body, were prepared according to the above method. The first and second magnetoelastic bodies were then stacked to obtain the high-resilience elastomer composite structure of Example 1. The angle between the first magnetization direction and the normal to the stacking surface is 20°; the angle between the second magnetization direction and the normal to the stacking surface is 50°. The angle between the first and second magnetization directions is 70°.
[0032] The performance of the high-resilience elastomer composite structure of Example 1 was tested. The material's cell density was 5 × 10⁻⁶. 3 cells / cm 3 Its compressive modulus is 5 MPa. After 100 cycles of 10% displacement compression, its elastic recovery rate is greater than 98%.
[0033] Example 2: Step 1: Surface modification of magnetic particles 0.8 g of neodymium iron boron magnetic powder with a particle size of 2 μm was taken and surface grafted with silane coupling agent KH570 to obtain modified neodymium iron boron magnetic powder. The method was the same as in Example 1 to enhance the interfacial bonding with the photocurable resin.
[0034] The surface-modified magnetic particles were mixed with 100 mL of n-hexane solvent and then subjected to ultrasonic treatment at 150 W for 30 minutes to form a uniform magnetic particle dispersion.
[0035] Step 2: Preparation of a mixture of magnetic particles and flexible polymer. The magnetic particle dispersion was mixed with 80 g of F39-T acrylate photocurable resin and 1.6 g of photoinitiator 819, and placed in a 60°C water bath. The mixture was magnetically stirred at 800 rpm for 120 minutes to ensure uniform dispersion of the particles and complete evaporation of hexane, thereby obtaining a magnetic particle flexible polymer mixture.
[0036] Step 3: Foaming and Cross-linking Curing A mixture of magnetic particles and flexible polymer was injected into a mold. Under magnetic field conditions, a strength of 30 mW / cm was first applied. 2 Irradiation with ultraviolet light for 20 seconds causes the resin to initially gel, fixing the chain structure of the magnetic particles and obtaining the precursor of the magnetoelastic.
[0037] The magnetoelastic precursor was then transferred to a high-pressure reactor, where N2 was used as the physical foaming agent. The saturation pressure was controlled at 15 MPa, the saturation time at 30 minutes, and the foaming temperature at 180°C. The magnetic field strength was 300 mT.
[0038] Rapidly depressurize and maintain foaming for 60 seconds, using a strength of 30 mW / cm. 2 Magnetoelastic material is obtained by irradiating it with ultraviolet light for 60 seconds. In practice, the foaming time can be between 5 and 60 seconds.
[0039] Step 4: Magnetization Treatment and Performance The sample was magnetized under a 30 kOe magnetic field. This yielded the magnetoelastic material of Example 2, which possesses a porous structure and magnetic particles.
[0040] Step 5: Preparation of composite elastomer Two magnetoelastic bodies, a first magnetoelastic body and a second magnetoelastic body, were prepared according to the above method. The first and second magnetoelastic bodies were then stacked to obtain the high-resilience elastomer composite structure of Example 2. The angle between the first magnetization direction and the normal to the stacking surface is 45°; the angle between the second magnetization direction and the normal to the stacking surface is 45°. The angle between the first and second magnetization directions is 90°.
[0041] The performance of the high-resilience elastomer composite structure in Example 2 was tested. The material's cell density was 2 × 10⁻⁶. 6 cells / cm 3 It has a compressive modulus of 2.3 MPa. It exhibits excellent photocuring precision and rapid recovery characteristics.
[0042] Example 3 Step 1: Preparation of magnetic particles and pore-forming agent Take 48 grams of samarium cobalt permanent magnet powder with a particle size of 30-50 μm and perform surface modification using KH550 (method as in Example 1). Prepare 100 grams of sodium chloride (NaCl) particles with a particle size of 100-200 μm as a pore-forming agent.
[0043] Step 2: Preparation of a mixture of magnetic particles and flexible polymer. Modified samarium cobalt magnetic powder, NaCl porogen, and 60 g of Ecoflex 00-30 prepolymer were mixed and magnetically stirred at 1200 rpm for 40 minutes at 80°C to ensure uniform mixing. Then, 60 g of Ecoflex curing agent was added, and magnetic stirring continued for 10 minutes. A flexible polymer mixture with magnetic particles was obtained. The porogen had a particle size of 1-500 μm and a volume percentage of 1-50 vol%.
[0044] Step 3: Curing and Foaming Under a pressure of -0.09 MPa, the mixture of magnetic particles and flexible polymer was vacuum degassed for 20 minutes and then injected into a mold. Under a magnetic field, it was heated in an oven at 80°C for 30 minutes to completely solidify the elastomer, obtaining the magnetoelastic precursor. The magnetic field was a parallel magnetic field of 30 mT.
[0045] After curing, the magnetoelastic precursor sample was immersed in 60°C deionized water and ultrasonically assisted leaching for 24 hours with 100W. The water was changed every 8 hours to completely remove the NaCl template and form a magnetoelastic.
[0046] Step 4: Magnetization Treatment The magnetoelastic sample was magnetized under a 60 kOe magnetic field. This yielded the magnetoelastic material of Example 3, which possesses a porous structure and magnetic particles.
[0047] Step 5: Preparation of composite elastomer Two magnetoelastic bodies, a first magnetoelastic body and a second magnetoelastic body, were prepared according to the above method. The first and second magnetoelastic bodies were then stacked to obtain the high-resilience elastomer composite structure of Example 3. The angle between the first magnetization direction and the normal to the stacking surface is 80°; the angle between the second magnetization direction and the normal to the stacking surface is 80°. The angle between the first and second magnetization directions is 160°.
[0048] The performance of the high-resilience elastomer composite structure in Example 3 was tested. It has a partially interconnected macroporous structure with a material pore density of 1×10⁻⁶. 8 cells / cm 3 With a compression modulus of 0.1 MPa, it exhibits extremely low starting pressure and ultra-high compressive deformation capacity.
[0049] When pressure is applied to the magnetized magnetoelastic bodies obtained in Examples 1-3, the pores of the magnetoelastic body are compressed, and the repulsive force between like poles of the magnetic particles is enhanced, providing a restoring force. The principle for applying pressure to the composite elastomers obtained in Examples 1-3 is as follows: Figure 4 As shown, by stacking two layers of porous magnetic elastomers with the same structure together, the magnetic force helps to restore the elastic pressure sensor, thereby further reducing the recovery time.
[0050] Comparative Example 1 Step 1: Preparation of surface-modified magnetic particles Take 50 g of samarium iron nitrogen magnetic powder with a particle size of 0.5 μm and place it in a 500 mL beaker. Add 200 mL of anhydrous ethanol, disperse by mechanical stirring, and then add 3 g of silane coupling agent KH550. Graft the magnetic particles by continuously stirring in a 60 °C water bath for 4 hours. After the reaction is complete, collect the modified magnetic powder by centrifugation at 8000 r / min, wash it three times with ethanol, and then dry it in a vacuum drying oven at 80 °C for later use.
[0051] Step 2: Preparation of a mixture of magnetic particles and flexible polymer. The surface-modified magnetic particles were mixed with 100 mL of n-hexane solvent and then subjected to ultrasonic treatment at 150 W for 30 minutes to form a uniform magnetic particle dispersion.
[0052] Take 100g of Sylgard 184 A PDMS prepolymer, mix it with the magnetic dispersion, place it in a 60℃ water bath, and magnetically stir at 1000 rpm for 120 minutes to make the particles uniformly dispersed and the n-hexane completely evaporated, thus obtaining a uniform magnetic particle flexible polymer mixture.
[0053] Step 3: Crosslinking and Curing Add 10 g of PDMS curing agent, Sylgard 184 B, to the obtained magnetic particle flexible polymer mixture and stir manually for 5 minutes to achieve initial mixing. Then place the mixture in a vacuum drying oven and degas at -0.095 MPa for 15 minutes to remove air bubbles introduced by stirring.
[0054] The degassed mixture is placed into a custom mold, a parallel magnetic field of 100 mT is maintained, and it is heated at 100°C for 60 minutes to cure the material completely cross-linked. The magnetic field is then removed to obtain a magnetoelastic.
[0055] Step 4: Magnetization Treatment The prepared magnetoelastic precursor was magnetized in a uniform magnetic field of 45 kOe. A magnetoelastic with magnetic particles, as described in Comparative Example 1, was obtained.
[0056] Step 5: Preparation of composite elastomer Two magnetoelastic bodies, a first magnetoelastic body and a second magnetoelastic body, were prepared according to the above method. The first and second magnetoelastic bodies were then stacked to obtain a high-resilience elastomer composite structure as described in Comparative Example 1. The angle between the first magnetization direction and the normal to the stacking surface is 20°; the angle between the second magnetization direction and the normal to the stacking surface is 50°. The angle between the first and second magnetization directions is 70°.
[0057] The tested material pore density of the magnetoelastic body in Comparative Example 1 was 5 × 10⁻⁶. 3cells / cm 3 The compression modulus is 30 MPa.
[0058] Comparative Example 2 Step 1: Preparation of surface-modified magnetic particles Take 50 g of samarium iron nitrogen magnetic powder with a particle size of 0.5 μm and place it in a 500 mL beaker. Add 200 mL of anhydrous ethanol, disperse by mechanical stirring, and then add 3 g of silane coupling agent KH550. Graft the magnetic particles by continuously stirring in a 60 °C water bath for 4 hours. After the reaction is complete, collect the modified magnetic powder by centrifugation at 8000 r / min, wash it three times with ethanol, and then dry it in a vacuum drying oven at 80 °C for later use.
[0059] Step 2: Preparation of a mixture of magnetic particles and flexible polymer. The surface-modified magnetic particles were mixed with 100 mL of n-hexane solvent and then subjected to ultrasonic treatment at 150 W for 30 minutes to form a uniform magnetic particle dispersion.
[0060] Take 100g of Sylgard 184 A PDMS prepolymer, mix it with the magnetic dispersion, place it in a 60℃ water bath, and magnetically stir at 1000 rpm for 120 minutes to make the particles uniformly dispersed and the n-hexane completely evaporated, thus obtaining a uniform magnetic particle flexible polymer mixture.
[0061] Step 3: Foaming and Cross-linking Curing Add 10 g of PDMS curing agent, Sylgard 184 B, to the obtained magnetic particle flexible polymer mixture and stir manually for 5 minutes to achieve initial mixing. Then place the mixture in a vacuum drying oven and degas at -0.095 MPa for 15 minutes to remove air bubbles introduced by stirring.
[0062] The degassed mixture was placed into a custom mold and heated to 100°C for 30 minutes to induce partial cross-linking and curing, thus obtaining a magnetoelastic precursor. Using CO2 as a physical foaming agent, the magnetoelastic precursor was transferred to a high-pressure reactor for critical physical foaming. The saturation pressure was controlled at 20 MPa, the saturation time at 120 minutes, and the foaming temperature at 160°C. The pressure was rapidly released, and the foaming state was maintained for 20 seconds to complete foaming and full cross-linking curing, resulting in the magnetoelastic precursor of Comparative Example 2.
[0063] Step 4: Preparation of composite elastomer Two magnetoelastic bodies, a first magnetoelastic body and a second magnetoelastic body, were prepared according to the above method. The first magnetoelastic body and the second magnetoelastic body were stacked to obtain the high-resilience elastomer composite structure of Comparative Example 2.
[0064] The tested material pore density of the magnetoelastic body in Comparative Example 2 was 5 × 10⁻⁶. 3 cells / cm 3 After 100 cycles of 10% compression, its elastic recovery rate is greater than 90%.
[0065] Example 4 The samples of the high-resilience elastomer composite structures obtained in Examples 1 and 2 were directly used as the elastic medium layer to form an elastic pressure sensor; the sensor was subjected to thousands or even tens of thousands of continuous pressure cycle tests. The test results show that the stability of the capacitive signal response is significantly improved.
[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the present invention. No reference numerals in the appended diagrams should be construed as limiting the scope of the claims. Furthermore, it is clear that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural.
[0067] However, those skilled in the art should understand that various modifications can be made to the preparation method of the high-resilience elastomer composite structure proposed in this invention without departing from the scope of this invention. Therefore, the scope of protection of this invention should be determined by the content of the appended claims.
Claims
1. A highly resilient elastomer composite structure, characterized in that, The product comprises a first magnetoelastic body and a second magnetoelastic body stacked together. The first magnetoelastic body layer has a first magnetization direction; the second magnetoelastic body has a second magnetization direction; the angle between the first magnetization direction and the second magnetization direction is less than 180°; wherein the first magnetoelastic body and the second magnetoelastic body are porous materials with a pore density of 10. 3 - 10 8 cells / cm 3 .
2. The high-resilience elastomer composite structure according to claim 1, characterized in that, The first magnetization direction and the second magnetization direction are mirror-symmetric with respect to the bonding surface.
3. The high-resilience elastomer composite structure according to claim 1, characterized in that, The raw materials of the magnetic elastomer include: modified magnetic particles, flexible polymer and curing agent, wherein, by mass, the ratio of magnetic particles to the flexible polymer is 1%-80%; and the ratio of the flexible polymer to the curing agent is 1:1-50:
1.
4. The high-resilience elastomer composite structure according to claim 3, characterized in that, The flexible polymer is one of a thermosetting resin, a photocurable resin, and a photothermal dual-curing resin; the thermosetting resin is one of PDMS, Ecoflex, or EPDM; the photocurable resin is Aiglus30 or F39-T acrylate resin; the photothermal dual-curing resin is modified epoxidized polybutadiene resin; the magnetic particles are one of samarium iron nitrogen magnetic powder, neodymium iron nitrogen magnetic powder, or neodymium iron boron / samarium cobalt permanent magnet powder; the particle size of the magnetic particles is 0.5 μm to 50 μm.
5. A method for preparing a highly resilient elastomer composite structure, characterized in that, Surface modification treatment is applied to the magnetic particles; The modified magnetic particles were dispersed in an organic solvent to obtain a magnetic particle dispersion. The magnetic particle dispersion is heated and stirred with a preset flexible polymer solution, and the organic solvent is removed to obtain a magnetic particle flexible polymer mixture. Under magnetic field conditions, a magnetic elastomer is obtained by cross-linking, curing, and foaming based on the magnetic particle flexible polymer mixture and curing agent. Two magnetoelastic bodies are taken. The first magnetoelastic body is magnetized to obtain a first magnetoelastic body with a first magnetization direction. The second magnetoelastic body is magnetized to obtain a second magnetoelastic body with a second magnetization direction. The first magnetoelastic body and the second magnetoelastic body are stacked to obtain a high-resilience elastomer composite structure. The magnetization intensity is 30kOe-60kOe. The angle between the first magnetization direction and the second magnetization direction is less than 180°.
6. The method for preparing a high-resilience elastomer composite structure according to claim 5, characterized in that, The pore density of the magnetoelastic is 10. 3 -10 8 cells / cm 3 .
7. The method for preparing a high-resilience elastomer composite structure according to claim 5, characterized in that, A method for obtaining a magnetic elastomer by cross-linking, curing, and foaming a mixture of the aforementioned magnetic particles and a curing agent under magnetic field conditions includes... After adding a curing agent to the magnetic particle flexible polymer mixture, stirring it evenly, and then performing vacuum degassing, the magnetic particle flexible polymer mixture undergoes a partial crosslinking curing reaction under magnetic field conditions to obtain a magnetic elastomer precursor. The magnetoelastic precursor is subjected to supercritical fluid foaming to obtain the magnetoelastic; wherein the pressure is 5-30 MPa, the saturation time is 10-120 min, the foaming temperature is 80-180℃, the foaming time is 5-60 s; and the magnetic field strength is 30-300 mT.
8. The method for preparing a high-resilience elastomer composite structure according to claim 5, characterized in that, A method for obtaining a magnetic elastomer by cross-linking, curing, and foaming a mixture of the aforementioned magnetic particles and a curing agent under magnetic field conditions includes... A curing agent and a pore-forming agent are added to the magnetic particle flexible polymer mixture. After stirring and vacuum degassing, the mixture undergoes a foaming reaction and a cross-linking curing reaction under a magnetic field. After removing the pore-forming agent, a magnetic elastomer is obtained. The pore-forming agent has a particle size of 1-500 μm, a volume fraction of 1%-50%, a curing temperature of 60-150℃, and a magnetic field strength of 30-300 mT.
9. The method for preparing a high-resilience elastomer composite structure according to claim 8, characterized in that, The pore-forming agent is one or more of sodium chloride, ammonium bicarbonate, ammonium carbonate, polyethylene glycol, and polyethylene oxide.
10. An elastic pressure sensor, characterized in that, It includes an elastic medium layer prepared from the elastomer composite structure of claim 1.